Strategies for Effective Nature Based Solutions to Mitigate Urban Heat Island in Delhi: An ENVI-met Based Simulation Study

<p dir="ltr">Rapid urbanization in Delhi has significantly intensified the Urban Heat Island (UHI) effect, where built-up areas experience higher temperatures than surrounding rural zones. The decline of green spaces and the expansion of impervious surfaces, like concrete and asphalt, have exacerbated this issue by trapping heat and reducing the cooling effects of natural landscapes. The UHI effect not only impacts the environment but also poses serious health risks, particularly to vulnerable populations such as children, the elderly, and low-income communities, who face heightened rates of heat-related illnesses and mortality during extreme heat events. While many studies in Delhi have documented temperature variations and identified contributing factors, few have offered practical, actionable solutions. Despite widespread recognition of the problem, there remains a lack of design-based intervention strategies on the urban scale. This gap highlights the need for a more holistic, solution-oriented approach to addressing the UHI effect in Delhi. This synthesis explores comparative nature-based solution strategies using simulation feedback analysis to assess the effectiveness of green roofs, green walls, tree canopies, and planting strips, relative to urban morphology, as practical design interventions for mitigating Urban Heat Island (UHI) effects in Delhi. The study is structured into three phases following a simulation-based methodology. The first phase involved a GIS-based analysis that identified Sadar Bazaar as an optimal urban test site. In the second phase, targeted nature based solution strategies were selected and integrated into predictive simulation scenarios using ENVI-met software. The third phase conducted a comparative analysis between existing and optimized scenarios, evaluating key parameters such as urban air temperature, surface temperature, and the Universal Thermal Climate Index (UTCI). The results demonstrated significant thermal reductions in the nature-based solutions-integrated scenarios, validating the hypothesis that strategic nature-based solutions incorporation can effectively mitigate the UHI effect in Delhi’s urban context.</p>